Honda CB900F

Double-cam Honda fours: aren't they nothing but trouble? Richard Stiles reveals the reality about owning a 30 year old classic Japanese superbike...

If you're looking for a sensibly-priced air-cooled four, then the DOHC CB750 is bound to be on the list. But why limit yourself to 70 horsepower when there's 95bhp to be had? The CB900 was Honda's attempt to cram the poke of an 1100 into a 750-sized package, and the race-bred 901cc CB proved to be pleasantly flexible in everyday use. 130mph is possible from the 16-valve motor but, better than that, the 900 was tuned for mid-range so responds enthusiastically to the throttle without constant cog swapping.

Handling isn't entirely ideal, however: look out for its inclination to flop into low speed corners and some high speed cornering sway, both exacerbated by worn or cheap replacement shocks and a jammed anti-dive system. Nothing out of the ordinary for the era…

Honda CB900F

Richard Stiles has owned several CBs, both 900s and the 1100, and talks us through some of the issues you can expect to encounter with these 30 year old motorcycles. 'They are very sensitive to valve clearances. The gap closes up causing poor starting and causing them to run rough when up to temperature. Most people spend ages and lots of money messing with carbs and ignition when it's just the valves holding open.'

That's the good news. The bad news is that the rumours you heard about Honda Hy-vo camchains are all true.

'All of the CB750/900/1100F models had camchain tensioner issues. There are two camchains; one very long chain driving the front (exhaust) cam and a shorter one linking the two cams. On my CB1100F the long camchain partly snapped and jammed up while starting. I had to rebuild the engine to replace the chain and tensioner but fortunately no valve-to-piston contact was made.'

1981 Honda CB900FB

So the moral of that story is to listen carefully to the engine before purchase and don't be tempted by a rattler unless you have negotiated the price right down to accommodate a full engine strip. Then once you own a CB, don't skimp on the scheduled maintenance.

Moving on to the cycle parts, Richard says 'the brakes on the early models (FZ and FA) are awful single piston calipers. The 4-piston calipers on FC and FD models are better but not really up to modern roads. I always fit braided hoses and a more modern master cylinder for better feel. NOS brake pads work better than modern sintered pads. You can end up with a good hydraulic system but no stopping power. Modern pads are too hard.'

On that note, it's worth experimenting with pads - we've had great results by trying different types which perform better at higher / lower temperatures, and have transformed wooden and weak single and dual-piston caliper set-ups into something at least effective and with some sensitivity. If you do use old pads, check them carefully before fitting and after initial use - at the first hint of delamination they must be replaced.

Richard also has some suggestions to help the handling. 'The rear shocks are the usual FVQ (FadeVeryQuick) units and all will be past it by now. Most people fit the cheap £50 pattern shocks but, again, these are awful. They are very hard with little damping. On the last 900 I fitted some secondhand Hagons and these were a lot better handling and more comfortable.

Honda CB900B

'Most of the original exhausts have rotted away. Try to replace them with a 4-into-2 system. I had a Sito 4-into-2 on my last 900 and this looked original and sounded good. Most people fit Motads but these seem to cause a flat spot through the mid-range. I had a Predator 4-into-1 on my previous CB900FZ. This worked better than the Motad but was very rorty at cruising speeds. It seemed to hit its noisiest at 50 to 70mph. Wemoto do a good 4-into-2 pattern system for reasonable money. Be aware that the FC and FD have rubber-mounted engines and use different exhausts to the FZ, FA and FB models.

Honda CB900B

'The FC and FD have boomerang Comstar wheels in silver with the CB1100FD (European) having gold lacquered boomerang Comstars. American CB1100 have cast wheels and a bikini fairing. All European models have clip-on handlebars while American models have higher bars as per usual.'

CB900s sell for between £1500 and £2500 at the moment: you'll get a decently roadworthy example with a full MoT and 40,000 or so miles on its clock for under £2000. Just check that it is a 900 and not a 750 in drag - only the bigger bike came with an oil cooler. You may also find some CB900C Custom versions being imported to the UK from the States - these provide a more relaxed ride with shaft drive and somewhat stunted performance, so are worth around 15% less than the 900F.

You may download pages from this site for your private use. No other reproduction, re-publication, re-transmission or other re-distribution of any part of this site in any medium is permitted except with the written consent of the copyright owner or in accordance with the provisions of the Copyright, Designs and Patents Act 1988.